In such buildings such as factories, business offices, shops, condominiums, warehouses, stations, gymnasiums, theaters, etc. and such structures as tunnels, underpasses, elevated railways, high level roads, bridges, etc. conduits through which typically power and communication cables and wires are passed and those through which a fluid such as gas flows are laid on the ceiling, side wall, floor, etc. of such buildings and structures.
For laying such conduits, generally channel rails, called saddle, are disposed in parallel with and as regularly spaced from each other and the conduits are fixed to the channel rails with clamps as placed perpendicularly thereto. In may such cases, the conduits have to be fixed to each of the channel rails and a plurality of conduits is fixed in parallel with each other on one channel rail. Conduits each having a predetermined length are longitudinally joined to each other in succession and a plurality of such joined conduits has to be disposed in parallel with and as regularly spaced from each other. Therefore, the conduits are provisionally fastened at selected points to such an extent that they will not be disengaged from the channel rails but are movable longitudinally of the channel rails (at the primary step), and thereafter they are securely clamped after correctly being positioned (at the secondary step). This manner of conduit clamping needs much labor and time.
The conduits are not only clamped to, as placed on, channel rails suspended by suspension bolts from the ceiling with the channel directed upward but also they are clamped, as applied from below, to channel rails fixed to the ceiling with the channel directed downward.
In the former case, the conduits, there is only a small space between the ceiling and the channel rails in many cases. In the latter case, the working person is compelled to face up with the neck bent about 90.degree. backward. This is a very painful posture.
Clamping of such conduit should desirably be simple, positive and safe. For reduction of costs and relief of pains, the clamping should be done efficiently with less labor and time. One of such conduit clamps is disclosed in the Japanese Unexamined Utility Model Publication No. 63-48085. This conduit clamp comprises a main body having a front T-shaped foot section and a retainer section contiguous from the foot section and which holds the semi-circumference of a conduit, a screw penetrated through a seat section provided on the opposite side of the foot section of the main body, and a flat vane fitted on the screw. For fixing a conduit, the vane is limited from rotating by applying the longitudinal end face thereof to the inner wall of the flange of a rail member and the vane is then lifted along the flange inner wall by tightening the screw, until the upper side of the vane touches the wall lower portion of the rail member.
For clamping a conduit to a channel rail with this conventional clamp, however, the vane must be inserted into the channel rail as postured for the longitudinal direction thereof to be parallel with the channel direction of the channel rail, and then it must be raised by tightening the screw many turns. Thus, this work cannot easily be done by one person. It needs at least two persons; one has to operate the conduit clamp while the other is holding the conduit as applied to the channel rail. Much labor and time are required for the provisional fixation of the conduit.
In the provisional fixing in the primary step, the screw has to be tightened. If the screw is turned counterclockwise, the vane will possibly leave the screw so that it will drop into the channel rail. Removing the vane from inside the rail will take some time, which will cause the work efficiency to be lower. In case the channel rail is installed with the channel directed downward, the vane disengaged from the screw by mistake (too much loosening of the screw or the like) or the conduit coming off the main body of the clamp will possibly drop to the person at the head or face, which will cause a fatal or critical bodily injury to him.
Also the U.S. Pat. No. 4,770,378 proposes that a vane is suspended with spring provided between a seat section and the head of a screw. When a conduit is provisionally fixed to a channel rail with this technique, the screw has to be pushed axially until the vane goes down to a free space under the drooping wall of the channel rail (primary step) and then the screw is tightened to turn the vane so as to be perpendicular to the channel rail (secondary step). Namely, this technique also needs two steps of operation, that is, much labor and time. The worker has to turn the wrist repeatedly many times, which causes him to be very fatigued. Since the screw must be turned in the provisional fixation of the conduit, if it is turned counterclockwise, the vane falls off the screw. Thus, the above-mentioned troubles are also unavoidable with this technique. The vane is held just in contact with the bottom side of the flat seat section; if a vibration is applied to the vane or the worker touches the screw carelessly by hand, the vane will be turned. Namely, it is difficult to hold the vane in parallel with the channel of the channel rail until the conduit is clamped.
In both these prior arts, the vane is limited from turning by applying both the longitudinal ends thereof to the inner walls of the channel-rail right and left flanges. This is also a problem. More particularly, the vane is actually nearly as long as the distance between the inner walls of the right and left flanges of the channel rail. The vane is likely to deflect if the tightening of the screw acts thereon; to avoid this, the vane should have an ample thickness. Thus, the clamp is massive and heavy as a whole, so it cannot be easily handled during transport or in clamping conduits to channel rails.
Because of its large length, the vane enters to a rather great depth in the curved retainer section of the main body when directed longitudinally in parallel with the channel in the channel rail. So the vane will be an interference in practice when the curved retainer section is applied to embrace a conduit. In this case, the vane must be turned 90.degree. once for a perpendicularity to the channel in the channel rail. When the clamp is set to the channel rail, the vane has to be turned 90.degree. again so as to be parallel to the channel in the channel rail. Otherwise, the vane cannot be introduced into the channel rail. For this adjustment, the screw must be turned (loosened or tightened), which will lead to a lower-work efficiency.
Also, the longitudinal end faces of the vane are caused to abut the flange inner walls so that the vane is blocked against rotating. Thus, depending upon the surface condition of the flange inner walls, the vane will be obliquely caught there and so the screw cannot be tightened or the vane will be raised as it is in the oblique position when the screw is tightened. Further, it cannot be visually checked from outside whether the vane is well directed or not. Therefore, the conduit will be secured to the channel rail with no sufficient contact of the vane with the drooping wall bottom faces of the channel-rail flanges. The conduit cannot be fixed stably and positively. Namely, the prior-art conduit clamps cannot satisfactorily secure the conduits to the channel rails.